[PATCH v4 01/15] genirq/msi: Silence set affinity failed warning

[Marek Vasut]

Various PCIe controllers that mux MSIs onto single IRQ line produce these
"IRQ%d: set affinity failed" warnings when entering suspend. This has been
discussed before [1] [2] and an example test case is included at the end
of this commit message.

Controller drivers which create MSI IRQ domain with MSI_FLAG_USE_DEF_CHIP_OPS
flag set and which do not override the .irq_set_affinity irqchip callback get
assigned default .irq_set_affinity = msi_domain_set_affinity() callback. That
is not desired on controllers where it is not possible to set affinity of each
MSI IRQ line to a specific CPU core due to hardware limitation.

Introduce dedicated flag MSI_FLAG_NO_AFFINITY, which keeps .irq_set_affinity
unset in case the controller driver did not assign the callback. This way, the
migrate_one_irq() code in cpuhotplug.c can exit right away, without printing
the aforementioned warning. The .irq_set_affinity implementations which only
return -EINVAL can be removed from multiple controller drivers.

```
$ grep 25 /proc/interrupts
 25:   0 0 0 0 0 0 0 0   PCIe MSI   0   Edge   PCIe PME

$ echo core > /sys/power/pm_test ; echo mem > /sys/power/state
...
Disabling non-boot CPUs ...
IRQ25: set affinity failed(-22). <---------- This is being silenced here
psci: CPU7 killed (polled 4 ms)
...
```

[1] https://lore.kernel.org/all/d4a6eea3c5e33a3a4056885419df95a7@kernel.org/
[2] https://lore.kernel.org/all/5f4947b18bf381615a37aa81c2242477@kernel.org/

Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
---
Cc: "Krzysztof Wilczyński" <kw at linux.com>
Cc: "Pali Rohár" <pali at kernel.org>
Cc: "Uwe Kleine-König" <u.kleine-koenig at pengutronix.de>
Cc: Aleksandr Mishin <amishin at t-argos.ru>
Cc: Anna-Maria Behnsen <anna-maria at linutronix.de>
Cc: Anup Patel <apatel at ventanamicro.com>
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list at broadcom.com>
Cc: Daire McNamara <daire.mcnamara at microchip.com>
Cc: Damien Le Moal <dlemoal at kernel.org>
Cc: Florian Fainelli <florian.fainelli at broadcom.com>
Cc: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
Cc: Jianjun Wang <jianjun.wang at mediatek.com>
Cc: Jim Quinlan <jim2101024 at gmail.com>
Cc: Jingoo Han <jingoohan1 at gmail.com>
Cc: Jisheng Zhang <Jisheng.Zhang at synaptics.com>
Cc: Jon Hunter <jonathanh at nvidia.com>
Cc: Jonathan Derrick <jonathan.derrick at linux.dev>
Cc: Jonathan Hunter <jonathanh at nvidia.com>
Cc: Joyce Ooi <joyce.ooi at intel.com>
Cc: Karthikeyan Mitran <m.karthikeyan at mobiveil.co.in>
Cc: Kishon Vijay Abraham I <kishon at kernel.org>
Cc: Koichiro Den <den at valinux.co.jp>
Cc: Lorenzo Pieralisi <lpieralisi at kernel.org>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Michal Simek <michal.simek at amd.com>
Cc: Nicolas Saenz Julienne <nsaenz at kernel.org>
Cc: Niklas Cassel <cassel at kernel.org>
Cc: Nipun Gupta <nipun.gupta at amd.com>
Cc: Nirmal Patel <nirmal.patel at linux.intel.com>
Cc: Rob Herring <robh at kernel.org>
Cc: Ryder Lee <ryder.lee at mediatek.com>
Cc: Shivamurthy Shastri <shivamurthy.shastri at linutronix.de>
Cc: Siddharth Vadapalli <s-vadapalli at ti.com>
Cc: Thierry Reding <thierry.reding at gmail.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh at renesas.com>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-mediatek at lists.infradead.org
Cc: linux-pci at vger.kernel.org
Cc: linux-renesas-soc at vger.kernel.org
Cc: linux-rpi-kernel at lists.infradead.org
Cc: linux-tegra at vger.kernel.org
---
V2: - Introduce MSI_FLAG_NO_AFFINITY to inhibit assignment
      of msi_domain_set_affinity()
V3: - Replace MSI_FLAG_USE_DEF_CHIP_OPS_NOAFF with MSI_FLAG_NO_AFFINITY
      and make MSI_FLAG_NO_AFFINITY into separate flag
    - Update commit message
    - Rebase on current linux-next
    - Use genirq/msi: subject prefix which is likely better fit now
    - Split off R-Car part of the patch
V4: No change
---
 include/linux/msi.h | 2 ++
 kernel/irq/msi.c    | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 9449797638255..b10093c4d00ea 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -554,6 +554,8 @@ enum {
 	MSI_FLAG_MSIX_CONTIGUOUS	= (1 << 19),
 	/* PCI/MSI-X vectors can be dynamically allocated/freed post MSI-X enable */
 	MSI_FLAG_PCI_MSIX_ALLOC_DYN	= (1 << 20),
+	/* PCI MSIs cannot be steered separately to CPU cores */
+	MSI_FLAG_NO_AFFINITY		= (1 << 21),
 };
 
 /**
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 5fa0547ece0c4..ca6e2ae6d6fc0 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -832,7 +832,7 @@ static void msi_domain_update_chip_ops(struct msi_domain_info *info)
 	struct irq_chip *chip = info->chip;
 
 	BUG_ON(!chip || !chip->irq_mask || !chip->irq_unmask);
-	if (!chip->irq_set_affinity)
+	if (!chip->irq_set_affinity && !(info->flags & MSI_FLAG_NO_AFFINITY))
 		chip->irq_set_affinity = msi_domain_set_affinity;
 }
 
-- 
2.43.0